Process for preparing a monoazo metal complex salt compound for charge control agent and toner for developing electrostatic images

ABSTRACT

Charge control agent comprising a metal complex salt compound of Formula (I) containing substantially no monoazo compound constituting the ligand thereof, toner containing the charge control agent, and process for manufacturing a metal complex salt compound of Formula (I), which comprises a metallizing reaction for metallizing a monoazo compound of Formula (II) with iron, nickel, aluminum, titanium or zirconium to produce a metal complex salt compound, in which metallizing reaction a monohydric or dihydric alcohol is used as a reaction-promoting solvent:                    
     wherein the substituents are as defined in the disclosure.                    
     and wherein the monoazo compound of formula (II) is prepared by a diazotizing coupling reaction in which a corresponding 4-Y-2-aminophenol wherein Y is the same as defined above is diazotized to the corresponding diazonium salt, and the diazonium salt is in turn coupled with a corresponding 6-R-2-naphthol wherein R is the same as defined above to form the monoazo compound of formula (II), the diazotizing coupling reaction being carried out in a monohydric alcohol as solvent.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a manufacturing process of a metalcomplex salt compound with a particular monoazo compound coordinated toa particular metal, more specifically to a manufacturing process whichis industrially advantageous and which enables the reduction of theenvironmental load, and to a charge control agent which can be producedby said manufacturing process, and a toner for developing electrostaticlatent images containing said charge control agent.

2. Description of the Prior Art

In copying machines, printers and other instruments based onelectrophotography, various toners containing a coloring agent, a fixingresin and other substances are used to visualize the electrostaticlatent image formed on the photoreceptor having a light-sensitive layercontaining an inorganic or organic photoconductive substance.

Toner chargeability is a key factor in electrostatic latentimage-developing systems. Thus, to appropriately control or stabilizethe amount of charges of a toner, a charge control agent providing apositive or negative charge is often added to the toner.

Of the conventional charge control agents in actual application, thoseproviding a negative charge for a toner include monoazo compound metalcomplex salt dyes, and metal complexes or metal salts of aromatichydroxycarboxylic acids such as alkylsalicylic acids.

However, many of the metal complexes of azo dye structure which havebeen proposed as charge control agents are generally unstable; forexample, they are likely to be decomposed deteriorated to lose theircharge control capability when exposed to mechanical friction or impact,electric impact, light irradiation, temperature or humidity changes,etc. Even with a practically applicable charge-providing property, suchmetal complexes are often unsatisfactory in charge stability or containimpurity chemical substances having no charge control effect dependingon the method and conditions of production, thus posing various problemsconcerning the stability and reliability of their quality as chargecontrol agents. In addition, there has recently been a demand for chargecontrol agents considering environmental concern and safety to the humanbody.

As charge control agents capable of resolving some of such problems,metal complex salt dyes (compounds) of the following structures, forexample, are available.

[In the two formulas, A⁺ is a counter ion such as H (hydrogen), analkali metal, ammonia or an amine.]

Such metal complex salt dyes are so-called 2:1 type azo metal complexdyes with two molecules of monoazo dye coordinated to one trivalentmetal atom.

Traditionally, the commonly used manufacturing process for this kind ofmetal complex salt dyes has been based on, for example, processes 1 and2 below.

1) A process wherein a monoazo compound (diazotizing coupling product)having a metallizable group constituting the ligand of the metal complexsalt dye is prepared: An aromatic amine derivative having a group suitedfor the formation of a metal complex salt is first diazotized. Theresulting diazonium salt is coupled to a coupling component having agroup suited for the formation of a metal complex salt. The monoazocompound produced by coupling is isolated from the aqueous medium.

2) A process wherein the monoazo compound prepared is metallized: Themonoazo compound is dissolved or suspended in water, a water-miscibleorganic solvent, or water-water-miscible organic solvent. Using ametallizing agent under the reaction conditions, the monoazo compound ismetallized. The resulting metal complex salt dye is isolated.

However, manufacturing processes like that described above are faulty inthat large amounts of waste liquid are produced, and that the processfor isolating the coupling product by saluting-out and filtration takesmuch time and material, and are problematic in that production costincreases as organic solvent separation and recovery and waste liquidtreatment are necessary for the process for carrying out a metallizingreaction using a water-miscible organic solvent, and that organicsolvent recovery is hampered as large amounts of water is necessary.

As a manufacturing process free from such drawbacks, there may bementioned the manufacturing process disclosed in Japanese PatentExamined Publication No. 22969/1996, which corresponds to U.S. Pat. No.5,204,453, issued Apr. 20, 1993. Using this method, a 1:2 type metalcomplex salt azo dye is obtained by performing diazotization, couplingand metallization in a one pot method (1-container method) withoutisolating the coupling product, in an aqueous system.

However, when a one-pot manufacturing process in common use or one asbased on a reaction in an aqueous system like that described in JapanesePatent Examined Publication No. 22969/1996, is applied to the productionof the metal complex salt compound desired in the present invention, thefollowing drawbacks are noted.

i) The solubility of the coupling comiponent is low.

ii) The production rate of the coupling product is slow, and the purityis low.

iii) In the subsequently metallized metal complex salt compound, thereobserved are impurity substances such as unreacted coupling product andinorganic salts.

In addition, certain conventional metal complex azo dyes for toners,which are excellent in fine pulverizability because of generally hardcrystallinity, have problems to be resolved; for example, when used intoners as charge control agents, they show insufficient compatibility(wettability) with the resins for toners, which in turn results inrelatively slow charge rise speeds; and the hard crystal is likely todrop off from toner particles during frictional charging as it ispartially exposed to the surface of toner particles.

The present invention was developed in view of the above problems in theprior art. Accordingly, it is an object of the present invention toprovide a high-purity metal complex salt compound with a monoazocompound having a particular alkyl group (4 to 12 carbon atoms) servingas a ligand, in a high yield in a short time.

It is another object of the present invention to reduce theenvironmental load by recovering and reusing the solvent.

It is still another object of the present invention to provide a chargecontrol agent which is excellent in charge-providing property andstability and good in dispersibility and wettability in resins fortoners, which, when used in a toner, produces a rapid rise of chargingand is unlikely to drop off from toner particles during frictionalcharging and which is excellent in storage stability (temporal stabilityof charge control characteristic) and durability (charge controlcharacteristic stability in the case of multiple repeated use of toner)and very safe as it contains no harmful heavy metals and yields negativeresults in the Ames test, and a method for its production.

It is a further object of the present invention to provide a toner fordeveloping electrostatic images which assures fixability and offsetresistance over a wide range of temperature, which is excellent inenvironmental resistance (charge characteristic stability to temperatureand humidity changes), storage stability (temporal stability of chargecharacteristic) and durability (charge characteristic stability in thecase of multiple repeated use of toner), which shows a rapid rise ofcharging and which is capable of forming stable copied images.

SUMMARY OF THE INVENTION

(1) The process for manufacturing of the present invention foraccomplishing the above objects is a process for manufacturing a metalcomplex salt compound of General Formula (I) below, which comprises ametallizing reaction for metallizing a monoazo compound of Formula (II)with iron, nickel, aluminum, titanium or zirconium to produce a metalcomplex salt compound, in which metallizing reaction a monohydric ordihydric alcohol is used as a reaction-promoting solvent:

in Formula (I),

R is a normal or branched alkyl group having 4 to 12 carbon atoms;

Y is halogen atom or normal or branched alkyl group having 1 to 5 carbonatoms;

each of p and q shows the number of monoazo compounds coordinated to themetal M; p is 1, 2, 3 or 4; q is 0, 1, 2 or 3; p+q is an integer of 1 to6;

each of L₁ and L₂ is —O—;

one of L₃ and L₄ is —O—, while the other is an —OH group or an —O⁻ ion;

M is iron, nickel, aluminum, titanium or zirconium;

(M^(x+))m represents an m number of metals of atomic valence x; m is aninteger of 1 to 4; x is an integer of 2 or more;

Z− is the negative charge in the parentheses; (A⁺)n is a hydrogen ion(H⁺) or an alkali metal ion (Na⁺, K⁺, etc.), n=Z;

in Formula (II),

R is a normal or branched alkyl group having 4 to 12 carbon atoms;

Y is halogen atom or normal or branched alkyl group having 1 to 5 carbonatoms.

(1-1) The metal complex salt compound manufacturing process of Term (1)preferably comprises a step of cooling the reaction mixture andseparating the metal complex salt compound precipitated, from the cooledmixture, after the aforementioned metallizing reaction is carried outusing a monohydric alcohol as a reaction-promoting solvent.

(1-2) In the metal complex salt compound manufacturing process of Term(1-1), it is preferable that the metallizing reaction is followed byseparating the metal complex salt compound precipitated, from theaforementioned cooled reaction mixture, recovering the monohydricalcohol in the form of an azeotrope with water, and reusing themonohydric alcohol in the azeotrope as the entire reaction-promotingsolvent or a part thereof.

(1-3) The metal complex salt compound manufacturing process of Term (1)preferably comprises a step of diazotizing coupling reaction to producea monoazo compound of Formula (II), in which diazotizing couplingreaction a monohydric or dihydric alcohol is used as areaction-promoting solvent.

Although the reaction-promoting solvent used in the diazotizing couplingreaction is preferably the same as the reaction-promoting solvent usedin the metallizing reaction, it may be different from the latter.

(1-4) The metal complex salt compound manufacturing process of Term(1-3) preferably comprises a step of cooling the reaction mixture andseparating the metal complex salt compound precipitated, from the cooledmixture, after the aforementioned diazotizing coupling reaction andmetallizing reaction are carried out, using a monohydric alcohol as areaction-promoting solvent.

(1-5) In the metal complex salt compound manufacturing process of Term(1-4), it is preferable that the metallizing reaction is followed byseparating the metal complex salt compound precipitated, from theaforementioned cooled reaction mixture, recovering the monohydricalcohol in the form of an azeotrope with water, and reusing themonohydric alcohol in the azeotrope as the entire reaction-promotingsolvent or a part thereof.

(1-6) In the metal complex salt compound manufacturing process of Term(1-4) or (1-5), it is preferable that the aforementioned diazotizingcoupling reaction is followed by separating the monoazo compoundprecipitated, from the reaction mixture, recovering the monohydricalcohol in the form of an azeotrope with water, and reusing themonohydric alcohol in the azeotrope as the entire reaction-promotingsolvent or a part thereof.

(1-7) In the metal complex salt compound manufacturing process of Term(1-2), (1-5) or (1-6), it is preferable that the water content in theaforementioned azeotrope is not more than 20% by weight.

(1-8) R in Terms (1) to (1-7) above is preferably a tert-octyl group.

(1-9) In the metal complex salt compound manufacturing process of Term(1) to (1-8) above, it is preferable that Y is chlorine atom.

(1-10) In the metal complex salt compound manufacturing process of Term(1) to (1-9) above, it is preferable that the reaction-promoting solventis one or more monohydric alcohols selected from the group consisting ofethanol, propanol, 2-propanol, butanol, isobutanol, sec-butanol,tert-butanol, amyl alcohol and isoamyl alcohol.

(1-11) The alcohol serving as a reaction-promoting solvent in Term(1-10) above is preferably 2-propanol.

(1-12) The metal complex salt compound manufacturing process of Terms(1-3), (1-4), (1-5) or (1-6) preferably comprises a step of obtaining amonoazo compound using 4-chloro-2-aminophenol as a diazo component,6-tertiary octyl-2-naphthol as a coupling component, and 2-propanol as areaction-promoting solvent; and a step of metallizing the monoazocompound obtained, in an aqueous solvent and 2-propanol as areaction-promoting solvent.

(1-13) In the metal complex salt compound manufacturing process of Term(1) to (1-12) above, it is preferable that iron chloride is used as ametallizing agent in the metallizing reaction.

(2) The charge control agent of the present invention comprises a metalcomplex salt compound of General Formula (I) below as an activeingredient, and containing substantially no monoazo compoundconstituting the ligand thereof:

in Formula (I),

R is a normal or branched alkyl group having 4 to 12 carbon atoms;

Y is halogen atom or normal or branched alkyl group having 1 to 5 carbonatoms;

each of p and q shows the number, of monoazo compounds coordinated tothe metal M; p is 1, 2, 3 or 4; q is 0, 1, 2 or 3; p+q is an integer of1 to 6;

each of L₁ and L₂ is —O—;

one of L₃ and L₄ is —O—, while the other is an —OH group or an —O⁻ ion;

M is iron, nickel, aluminum, titanium or zirconium;

(M^(x+))m represents an m number of metals of atomic valence x; m is aninteger of 1 to 4; x is an integer of 2 or more;

Z− is the negative charge in the parentheses; (A⁺)n is a hydrogen ion(H⁺) or an alkali metal ion (Na⁺, K⁺, etc.), n=Z.

This charge control agent contains the aforementioned metal complex saltcompound at a high purity (not less than about 90% by weight, preferablynot less than about 95% by weight, more preferably not less than about99% by weight), and can be produced by the metal complex salt compoundmanufacturing process described in Term (1) to (1-13) above.

(2-1) M in Term (2) above is desirably trivalent or divalent iron.

(2-2) The pH of the charge control agent of Term (2) or (2-1) above ispreferably 7 to 12.

(2-3) The charge control agent of Term (2) to (2-2) above yieldsnegative results in the Ames test.

(3) The toner of the present invention for developing electrostaticimages contains the charge control agent of Term (2) to (2-3) above, aresin for toners, and a coloring agent.

According to the process for manufacturing of the present invention, ametal complex salt compound whose content of unreacted monoazo compoundis much smaller than that with conventional compounds, or a metalcomplex salt compound containing substantially no unreacted monoazocompound, can be produced in a high yield in a short time, and theproducts obtained by this manufacturing process is excellent in chargecontrol stability, charge rise speed, storage stability, durability,etc., as charge control agents.

According to the invention of Term (1-1) or (1-4) above, a metal complexsalt compound of better purity can be produced in a high yield in ashort time, and the products obtained by these manufacturing processesare more excellent in charge control stability, charge rise speed,storage stability, durability, etc., as charge control agents.

In addition, according to the invention of Term (1-2), (1-5) or (1-6),significant production cost reduction and environmental load mitigationcan both be realized by reusing the monohydric alcohol in the azeotroperecovered.

The charge control agent of the: present invention is excellent innegative charge-providing property and stability and good indispersibility and wettability in resins for toners. When used in atoner, it produces a rapid rise of charging and is unlikely to drop offfrom toner particles during frictional charging. It is also excellent instorage stability and durability and very safe as it contains no harmfulheavy metals and yields negative results in the Ames test.

Containing the charge control agent of the present invention, the tonerof the present invention for developing electrostatic images assuresfixability and offset resistance over a wide range of temperature, isexcellent in environmental resistance, storage stability and durability,shows a rapid rise of charging, and is capable of constantly formingcopied images.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an FD-MS spectrum of the iron complex salt compound obtainedin Example 1.

FIG. 2 is a TIC spectrum by the FD method of the iron complex saltcompound obtained in Example 1.

FIG. 3 shows a high performance liquid chromatography of the monoazocompound obtained in Example 7.

FIG. 4 shows a high performance liquid chromatography of the monoazocompound obtained in Comparative Example 2.

FIG. 5 shows the charge characteristics of a developer using the tonerof Example I and a developer using the toner of Comparative Example I.

DETAILED DESCRIPTION OF THE INVENTION

Synthesis of Monoazo Compound [Formula (II)]

A monoazo compound (also referred to as coupling product) of Formula(II), used in the metal complex salt compound manufacturing process ofthe present invention, can be prepared by carrying out a diazotizingcoupling reaction using a monohydric or dihydric alcohol, preferably2-propanol, as a reaction-promoting solvent.

A preferred embodiment is as follows:

First, to a mixed liquor of 4-chloro-2-aminophenol [diazo componenthaving a group suited for metal complex salt formation (hydroxylgroup)], 2-propanol [reaction-promoting solvent], and hydrochloric acid(hydrochloric is acid adjusted to 35%), sodium nitrite (aqueous solutionadjusted to 36%) is added, and this mixture is stirred within thetemperature range from 0 to 5° C. for 1 to 3 hours to diazotize the4-chloro-2-aminophenol.

Next, a diazotized solution (aforementioned diazotized compound solutionwith the NaCl precipitated therein removed by filtration) is added dropby drop to a mixed liquor (kept at 45 to 50° C.) of 6-tertiaryoctyl-2-naphthol [coupling component having a group suited for metalcomplex salt formation (hydroxyl group)], an aqueous solution of sodiumhydroxide [aqueous solution of hydroxide of alkali metal (Na, K, etc.),and 2-propanol [reaction-promoting solvent], and this mixture is stirredfor 2 to 3 hours to couple the diazonium salt to the coupling component.

By collecting by filtration the coupling product precipitated andwashing with water, a wet cake of a water content of about 50 to 60% isobtained. By drying the wet cake (e.g. by hot air drying or paddledrying), a high-purity monoazo compound of the following structure canbe isolated in the form of powder.

[In this formula, Oct(tert-) is a tertiary octyl group.]

The monoazo compound (coupling product) obtained as described above isof high purity (not less than 95% by weight) and high yield (not lessthan 90%), because the NaCl produced as a byproduct from the process forits diazotization can be removed, and because the effect of thereaction-promoting solvent accelerates the reaction and increases thereaction rate.

Synthesis of Metal Complex Salt Compound [Formula (I)]

The metal complex salt compound manufacturing process of the presentinvention may be such that a dry product or wet cake of a monoazocompound [Formula (II)] obtained by the method described above ismetallized (preferably with iron) using a metallizing agent (preferablyferric chloride) with a monohydric or dihydric alcohol, preferably2-propanol, serving as a reaction-promoting solvent. By this method, ametal complex salt compound whose content of unreacted monoazo compoundis much smaller than that with conventional compounds, or a metalcomplex salt compound containing substantially no unreacted monoazocompound, can be produced in a high yield in a short time.

A preferred embodiment is as follows:

The aforementioned monoazo compound [Formula (II)], preferably acoupling product obtained as described above is gradually added to amixed liquor of 2-propanol [reaction-promoting solvent] and anappropriate amount of an aqueous solution of sodium hydroxide (aqueoussolution of hydroxide of alkali metal (Na, K, etc.), i.e., alkalinemedium), and this mixture is refluxedunder heating for 1 to 2 hours todissolve the monoazo compound. Next, a necessary amount of ferricchloride [metallizing agent] is added, and this mixture is refluxedunder heating at 75 to 85° C., preferably 80 to 85° C., to metallize themonoazo compound.

After cooling or allowing to cool (usually not higher than about 50° C.,preferably not higher than 40° C., more preferably not more than 30° C.)the mixture, the metal complex compound precipitated in the solvent iscollected by filtration, washed with water, and dried (e.g. by hot airdrying or paddle drying), an iron complex salt compound of Formula (III)below is isolated in the form of blackish brown powder.

[In Formula (III), R, p, q, L₁, L₂, L₃, L₄, m, n, Z− and (A⁺) have thesame definitions as those given above.]

Specifically, the iron complex salt compound obtained is usually amixture of a 2:1 type iron complex salt compound below wherein twomonoazo compounds are coordinated to one Fe(III)

and all or some of 3:2 type metal complex salt compounds of Formula(III) wherein p+q=3 (p is 1, 2 or 3; q is 0, 1 or 2) and m=2; 4:2 typemetal complex salt compounds wherein p+q=4 (p is 1, 2, 3 or 4; q is 0,1, 2 or 3) and m=2; 6:4 type metal complex salt compounds wherein p+q=6(p is 3 or 4; q is 2 or 3) and m=4; and polymeric metal complex saltcompounds (see Examples). In the case of such an iron (III) complex saltcompound, it is usually obtained as a mixture containing a 2:1 type ironcomplex salt compound, a 3:2 type iron complex salt compound, and a 4:2type iron complex salt compound.

Although the production ratio of each compound obtained as such amixture varies depending on the reaction conditions for the desiredproduct, it is impractical to separate a single compound from such amixture; furthermore, the metal complex salt compound in the presentinvention need not be a single substance. However, each product can beidentified by FD-MS analysis.

It is desirable that the filtrate obtained by collecting by filtrationthe coupling product (monoazo compound) precipitated after theaforementioned diazotizing coupling reaction, from the reaction mixture,and/or the filtrate obtained by collecting by filtration the metalcomplex salt compound precipitated after the aforementioned metallizingreaction, from the cooled reaction mixture, be separated into water andan azeotrope of 2-propanol and water (2-propanol:water=87.64:12.36[ratio by weight]) by distillation, and that the 2-propanol (monohydricalcohol) in the azeotrope be reused as the entire reaction-promotingsolvent or a part thereof in monoazo compound synthesis and/or metalcomplex salt compound synthesis as described above. In such reuse ofmonohydric alcohol, the azeotrope can be used as is. Although purity canbe further increased by azeotropic distillation or extractivedistillation, it is undesirable because of increased cost.

The monohydric alcohol serving as a reaction-promoting solvent used inthe manufacturing process of the present invention is exemplified bymethanol; monohydric alcohols having 2 to 5 carbon atoms which makeazeotropic mixtures, such as ethanol, propanol, 2-propanol(isopropanol), butanol, isobutanol, sec-butanol, tert-butanol, amylalcohol and isoamyl alcohol; and monohydric alcohols such as ethyleneglycol monoalkyl (1 or 2 carbon atoms) ethers.

The dihydric alcohol is exemplified by dihydric alcohols such asethylene glycol.

The reaction-promoting solvent may be any one, as long as it is capableof dissolving the diazo component (e.g. 4-chloro-2-aminophenol) and thediazotized product thereof in an acidic aqueous solution in thediazotization process, enables the separation and removal of a fairamount of the byproduct salt, and is capable of dissolving the couplingcomponent (e.g. 6-tertiary octyl-2-naphthol) in an alkaline aqueoussolution in the coupling process, and as long as the coupling productproduced in this reaction solvent system is precipitated (Areaction-promoting solvent may be used if the coupling product producedis substantially precipitated when the solvent is diluted in water. Ifthe coupling product produced can be precipitated in thereaction-promoting solvent without such dilution, suchreaction-promoting solvent is more preferable.). Preferred asreaction-promoting solvents are monohydric alcohols having 1 to 5 carbonatoms, with greater preference given to 2-propanol. In cases where themonohydric alcohol in the azeotrope is reused, its purity is preferablyas high as possible. Particular preference is given to 2-propanol havinga purity of not lower than 87.6%.

Although the reaction-promoting solvent used in the metallizationprocess for the monoazo compound may be the same as that used in thediazotizing coupling process, or not, it is desirably such that themonoazo compound dissolves during heating in a mixed solvent (alkaline)with water. In addition, the reaction-promoting solvent is preferablysuch that the metallized compound (desired product) is precipitated bycooling or allowing to cool. From the viewpoint of recovery andseparation and recycled use, the former is preferably the same as thelatter.

The amount of reaction-promoting solvent used in the diazotizingcoupling process and metallizations process is desirably minimized fromthe viewpoint of material cost, as long as it meets the variousconditions described above. When 2-propanol, for example, is used as areaction-promoting solvent, its amount may be about not less than 4times by weight the amount of the diazo component, about not less than 3times by weight the amount of the coupling component, and about not lessthan 1.8 times by weight the amount of the monoazo compound in themetallization process.

In cases where the azeotrope of 2-propanol and water(2-propanol:water=87.64:12.36 [ratio by weight]) is used, it ispreferable that its amount be about 4 to 9 times by weight the amount ofthe diazo component, about 3 to 6 times by weight the amount of thecoupling component, and about 1.1 to 3.5 times by weight the amount ofthe monoazo compound in the metallizing process. If the amount of use issmaller than the lower limit of the preferable range, the purity andyield of the monoazo compound tends to fall in the diazotizing couplingreaction, and the dissolution of the monoazo compound and the smoothprogress of the reaction tend to be hampered so that the purity of themetal complex salt compound tends to be low after the metallizingreaction.

Other organic solvents useful for the monoazo compound metallizingreaction (the metallizing reactions excluded from the metallizingreactions of the present invention) include traditionally commonly usedethylene glycol dialkyl ether-series organic solvents such as ethyleneglycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether(diglyme), ethylene glycol diethyl ether, triethylene glycol dimethylether (triglyme) and tetraethylene glycol dimethyl ether (tetraglyme);and aprotic polar solvents such as N,N-dimethylformamide,N,N-dimethylacetamide, N-methyl-2-pyrrolidone and dimethyl sulfoxide.

The metal atoms capable of chelate binding with the two —OH groups inthe monoazo compound (coupling product) in the metal complex saltcompound in the present invention are the trivalent metals iron (III),aluminum (III), is nickel (III), titanium (III) and zirconium (III), thedivalent metals iron (II) and nickel (II), and the tetravalent metalstitanium (IV) and zirconium (IV). In the present invention, divalent ortrivalent iron, especially trivalent iron is preferred from theviewpoint of environmental issues and manufacturing cost.

Examples of metallizing agents preferably used to produce the metalcomplex salt compound in the present invention include e.g., metal saltcompounds, and particularly iron compounds such as ferric chloride,ferric sulfate, ferrous sulfate, ferric nitrate and ferrous ferricchloride (Fe₃Cl₇.xH₂O, Fe₃Cl₈.xH₂O); aluminum compounds such as aluminumsulfate and basic aluminum acetate; and metal chlorides such as nickelchloride, titanium trichloilride (III), titanium tetrachloride (IV),zirconium chloride (III) and zirconium chloride (IV). Preferred from theviewpoint of the objects of the present invention, material cost andease of handling is ferric chloride, especially an aqueous solution offerric chloride.

The amount of metallizing agent used is ½ to 2 atomic equivalents,preferably ½ to ⅔ atomic equivalents per equivalent of the monoazocompound serving as the ligand.

Although the tert-octyl group is particularly preferable as thesubstituent R in the monoazo compound and the metal complex saltcompound in the present invention (normal or branched alkyl group Rhaving 4 to 12 carbon atoms in the various formulas above), otherexamples include t-butyl group, isoamyl group, hexyl group, n-octylgroup, 2-ethylhexyl group, n-nonyl group, n-decyl group and dodecylgroup.

Examples of the substituent Y in the monoazo compound and the metalcomplex salt compound in the present invention (halogen atom or normalor branched alkyl group Y having 1 to 5 carbon atoms in the variousformulas above) include halogens such as Cl, Br and I and alkyl groupshaving 1 to 5 carbon atoms such as methyl group, ethyl group, isopropylgroup, propyl group, butyl group, isobutyl group, tert-butyl group, amylgroup, isoamyl group and tert-amyl group. Preference is given to Cl atomor tert-butyl group.

In addition, it is particularly preferable that the charge control agentin the present invention is an iron complex salt compound of Formula(IV) below.

[In Formula (IV), p, q, L₁, L₂, L₃, L₄, m, n, Z− and (A⁺) have the samedefinitions as those given above; R is a tertiary octyl group {i.e.,Oct(tert-)}].

Iron complex salt compounds of Formula (IV) above include, for example,the groups of compounds shown below.

(i) Group of 2:1 type metal complex salt compounds (dyes) of Formula(IV) wherein p=2, q=0, (M^(x+))m=(Fe³⁺)₁, and (A⁺)n=(A⁺)n, hereinafterdescribed as Formula (a) below:

[(AP-OB)₂.(Fe³⁺)](A⁺)  Formula (a):

(ii) Group of 3:2 type metal complex salt compounds of Formula (IV)wherein p+q=3, (M^(x+))m=(Fe³⁺)₂, and (A⁺)n=(A⁺)n, hereinafter describedas Formula (b) below:

[(AP-OB)₃.(Fe³⁺)₂](A⁺)n  Formula (b):

(iii) Group of 4:2 type metal complex salt dyes of Formula (IV) whereinp+q=4, (M^(x+))m=(Fe³⁺)₂, and (A⁺)n=(A⁺)n, hereinafter described asFormula (c) below:

[(AP-OB)₄.(Fe³⁺)₂](A⁺)n  Formula (c):

(iv) Group of 1:1 type metal complex salt compounds of Formula (IV)wherein p=1, q=0, (M^(x+))m=(Fe²⁺), and (A³⁰ )n=(A³⁰ )o (exclusivelyx=2), hereinafter described as Formula (d) below:

[(AP-OB)₁.(Fe²⁺)]  Formula (d):

In Formulas (a) through (d) above, (AP-OB) is a ligand via which amonoazo compound (Formula II) having two metallizable OH groups iscoordinated to iron as metal ion. The group of compounds (iron complexsalt compounds) of Formula (a) are iron complex salt compounds whereintwo monoazo compounds are coordinated to one iron ion. The group ofcompounds of Formula (b) are iron complex salt compounds wherein threemonoazo compounds are coordinated to two iron ions. The group ofcompounds of Formula (c) are iron complex salt compounds wherein fourmonoazo compounds are coordinated to two iron ions. The group ofcompounds of Formula (d) are iron metal complex salt compounds whereinone monoazo compound is coordinated to one divalent iron ion. The numbern of (A³⁰ ), which serves as counter ion, is necessary to neutralize thenegative charge (Z−) possessed by the mother compound, and meets. therequirement of Z=n.

The charge control agent in the present invention may be any one kind ofiron complex salt compound selected from the aforementioned groups ofcompounds, and may, for example, be a mixture of two kinds of ironcomplex salt compounds respectively selected from the two groups ofcompounds of Formulas (a) and (b), a mixture of two kinds of ironcomplex salt compounds respectively selected from the two groups ofcompounds of Formulas (a) and (b), and one kind of iron complex saltcompound selected from the group of compounds of Formula (c) or, as thecase may be, Formula (d), or a mixture of three or four kinds of ironcomplex salt compounds respectively selected from the three or fourgroups of compounds of Formulas (a), (b) and (c) and, as the case maybe, Formula (d).

In referring to the term “one kind” as used herein, the metal (iron)chelate binding condition of the ligand (AP-OB) and kind of counter ionA⁺ do not matter. In other words, each of L₁ through L₄ in Formula (IV)forms —O— (e.g., L₁ and L₂ above) basically as coordinated to iron(metal M); however, cases where either of the two metallizable hydroxylgroups (OH) of the monoazo compound is chelate bound are also included(e.g., L₃ and L₄ above). The counter ion A⁺ is H⁺, Na⁺, or the like, andmay be present alone or in mixture. The counter ion A⁺ can depend on thereaction conditions and final product takeout conditions (pH). Forexample, if the product is taken out in a hydrochloric acid acidicatmosphere, the counter ion A³⁰ can be H⁺. If the product is taken outin an alkaline atmosphere, the counter ion A⁺ can, for example, be asodium salt. In addition, if the product is taken out under nearlyneutral conditions, such counter ions can be present in mixture.

Next, five examples of coordinate bonds for the monoazo compound in ironcomplex salt compounds of Formula (IV) above are given withoutspecifying the number of ligands and the charge number of Fe.

Metal (iron) complex salt compounds respectively of Formulas (a), (b),(c), etc. above are compounds identified by mass analysis (FD-MSspectral analysis etc.), and some of them are disclosed in JapanesePatent Unexamined Publication No. 7164/1999, which corresponds to U.S.Pat. No. 6,197,467, issued Mar. 6, 2001. The iron complex salt compoundsobtained by the method of the present invention were also identified bythe FD-MS technique, which is known to preferentially demonstratemolecular ion peaks.

In addition, the iron complex salt compound of the present inventionobtained as described above yields, negative results in the Ames test,which provides an index of safety (see Examples). This is important fromthe viewpoint of the safety of charge control agents and toners forelectrophotography to the human body.

It should be noted that many of the metal complex salt dyes produced bycommonly known methods are generally crystalline. For example, the ironcomplex salt compound metallized in ethylene glycol, disclosed inJapanese Patent Unexamined Publication No. 7164/1999 (Example 2), hasbeen shown to be crystalline on the basis of its X-ray diffractionspectrum. The iron complex salt compound of the present invention assynthesized by the method described in Examples below also yielded anX-ray diffraction spectrum providing evidence for crystallinity.

As examples of metal (iron) complex salt compounds in the presentinvention, there may be mentioned Example Compounds (1) through (15)below and mixtures of two or more kinds thereof.

(1) [(AP-OB)₂.(Fe³⁺)](Na⁺)

(2) [(AP-OB)₂.(Fe³⁺)](K⁺)

(3) [(AP-OB)₂.(Fe³⁺)](H⁺)

(4) [(AP-OB)₃.(Fe³⁺-Fe³⁺)](Na⁺)

(5) [(AP-OB)₃.(Fe³⁺-Fe³⁺)](H⁺)

(6) [(AP-OB)₃.(Fe′³⁺)₂]

(7) [(AP-OB)₃.(Fe²⁺/Fe³⁺)](Na⁺)

(8) [(AP-OB)₄.(Fe³⁺-Fe³⁺)](Na⁺)

(9) [(AP-OB)₄.(Fe³⁺-Fe³⁺)](Na⁺)₂

(10) [(AP-OB)₄.(Fe³⁺-Fe³⁺)](H⁺)₂

(11) [(AP-OB)₄.(Fe²⁺/Fe³⁺)](Na⁺)

(12) [(AP-OB)₃.(Fe²⁺)₂](Na⁺)₂

(13) [(AP-OB).(Fe²⁺)]

(14) [(AP-OB).(Fe³⁺)]⁺[(AP-OB)₂.(Fe³⁺)]

(15) [(AP-OB)₆.(Fe³⁺)₄]^(Z−)(Na⁺)_(n)

As other examples of metal complex salt compounds in the presentinvention, there may be mentioned compounds below.

The charge control agent of the present invention shows goodcompatibility (wettability) with resins for toners because of the effectof the substituent R. Although it is not subject to limitation as tophysical and chemical properties, its mean particle diameter isdesirably not more than 20 μm, preferably not more than 10 μm, and morepreferably not more than 5 μm. The pH of the charge control agent ispreferably 7 to 12. Preferred iron complex salt compound as the chargecontrol agent is sodium complex having the pH of not less than 7.

Next, the toner of the present invention for developing electrostaticimages comprises the charge control agent of the present invention, aresin for toners, and a coloring agent. The metal complex salt compoundconstituting the charge control agent may be a single compound or amixture of several compounds.

The toner of the present invention for developing electrostatic imagesis desirably formulated with the charge control agent of the presentinvention at 0.1 to 10 parts by weight per 100 parts by weight of theresin for toners. More preferably, the formulation amount of the chargecontrol agent is 0.5 to 5 parts by weight per 100 parts by weight of theresin for toners.

Examples of resins useful in the toner of the present invention includethe following commonly known resins for toners (binder resins).Specifically, useful resins include thermoplastic resins such as styreneresin, styrene-acrylic resin, styrene-butadiene resin, styrene-maleicacid resin, styrene-vinyl methyl ether resin, styrene-methacrylatecopolymer, polyester resin and polypropylene resin. These resins may beused singly or in blends of several kinds. In addition, the chargecontrol agent of the present invention can also be used as contained inelectrostatic powder paints to control (enhance) the charge of the resinpowder. In such case, useful resins for paints include, for example,thermoplastic resins of the acrylate series, polyolefin series,polyester series or polyamide series; and thermosetting resins of thephenol series, epoxy series, polyester series, or the like; these resinsmay be used singly or in blends of several kinds.

In the toner of the present invention for developing electrostaticimages, various commonly known dyes and pigments can be used as coloringagents. Examples of useful coloring agents include organic pigments suchas Quinophthalone Yellow, Isoindolinone Yellow, Perinone Orange,Perinone Red, Perylene Maroon, Rhodamine 6G Lake, Quinacridone Red,Anthanthron Red, Rose Bengale, Copper Phthalocyanine Blue, CopperPhthalocyanine Green and diketopyrrolopyrrole pigments; and inorganicpigments and metal powders such as Carbon Black, Titanium White,Titanium Yellow, Ultramarine, Cobalt Blue, red iron oxide, aluminumpowder and bronze.

The toner of the present invention for developing electrostatic imagescan, for example, be produced as described below.

Specifically, a toner having a mean particle diameter of 5 to 20 μm canbe obtained by thoroughly mixing a resin for toners as described above,a coloring agent (preferably Carbon Black), and the charge control agentof the present invention, and, if necessary, a magnetic material (e.g.,fine powder of ferromagnetic metal such as iron or cobalt, ferrite), afluidizing agent (e.g., silica, aluminum oxide, titanium oxide), ananti-offset agent (e.g., wax, low-molecular weight olefin wax) and otheradditives, using a ball mill or another mechanical mixer, subsequentlykneading the mixture in a molten state using a hot kneader such as aheat roll, kneader or extruder, cooling and solidifying the mixture,then pulverizing the solid and classifying the resulting particles bysize.

Other applicable methods include the method in which starting materialsare dispersed in a binder resin solution and subsequently spray dried toyield the desired toner, and the polymerization method in which a givenset of starting materials are mixed in a monomer to constitute a binderresin to yield an emulsified suspension, which is then polymerized toyield the desired toner.

When the toner of the present invention is used as a two-componentdeveloper, development can be achieved by the magnetic brush developingprocess or the like using the toner of the present invention in mixturewith carrier powder.

Any commonly known carrier can be used without particular limitation.Examples of the carrier include iron powder, nickel powder, ferritepowder and glass beads about 50 to 200 μm in particle diameter, and suchmaterials as coated with acrylate copolymer, styrene-acrylate copolymer,styrene-methacrylate copolymer, silicone resin, polyamide resin,ethylene fluoride resin, or the like.

When the toner of the present invention is used as a one-componentdeveloper, an appropriate amount of a fine powder of a ferromagneticmaterial, such as iron powder, nickel powder or ferrite powder, may beadded and dispersed in preparing the toner as described above. Examplesof developing processes which can be used in this case include thecontact development process and the jumping development process.

EXAMPLES

The present invention is hereinafter described in more detail by meansof the following examples, which are not to be construed as limitative.In the description below, “part(s) by weight” is referred to as“part(s)” for short.

Example 1

Synthesis of Monoazo Compound

After 45.7 parts of 4-chloro-2-aminophenol, 110.5 parts of 35%hydrochloric acid and 244.9 parts of 2-propanol were stirred and mixed,this mixture was cooled externally to 0 to 5° C. To this mixture, 65.8parts of 36% sodium nitrite was added, and this was followed by stirringwithin the temperature range from 0 to 50° C. for 2 hours to diazotizethe 4-chloro-2-aminophenol.

Next, the NaCl which precipitated in this diazotized compound solutionwas filtered off; the filtrate obtained was added drop by drop to amixed liquor (kept at 45 to 50° C.) of 244.9 parts of 2-propanol, 64parts of a 48.7% aqueous solution of sodium hydroxide and 81.6 parts of6-tertiary octyl-2-naphthol; this mixed liquor was stirred for 2 hoursto carry out a coupling reaction, followed by cooling (not more than 30°C.); the monoazo compound precipitated was then collected by filtration,washed with water, and dried, to yield 115.3 parts (yield 90%) of amonoazo compound of the following structure:

Elemental analysis results for the monoazo compound obtained (AP-OB) areshown in Table 1.

TABLE 1 C H N Cl Na Actual 70.45 6.75 6.33 6.94 907(ppm) measurementvalues Calculated 70.15 6.62 6.82 7.78 — values

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 2.

Synthesis of Iron Complex Salt Compound

After 100 parts of the monoazo compound obtained above was graduallyadded to a mixed liquor of 187 parts of 2-propanol and 40 parts of a48.7% aqueous solution of sodium hydroxide, followed by 2 hours ofrefluxing under heating at 80° C., 50 parts of 38% ferric chloride wasadded, followed by 2 hours of refluxing under heating at 80° C., toachieve metallization.

Next, this reaction mixture was cooled to 30° C. and dispersed in 1,025parts of water, and stirred at 30° C. for 1 hour; the productprecipitated was collected by filtration and washed with water, thendried, to yield 113 parts of an iron complex salt compound as a blackishbrown powder.

The FD-MS spectrum of the iron complex salt compound obtained is shownin FIG. 1 (the abscissa indicates M/Z [mass/charge]; the ordinateindicates relative abundance [relative detection strength of ion]).

From FIG. 1, it is found that this iron complex salt compound is amixture of:

(1) a 2:1 type iron complex salt compound wherein two monoazo compoundsare coordinated to one Fe(III), i.e., [(AP-OB)₂.(Fe³⁺)](Na⁺) MW:896;

(4) a 3:2 type iron complex salt compound wherein three monoazocompounds are coordinated to two Fe(III), i.e.,[(AP-OB)₃.(Fe³⁺-Fe³⁺)](Na⁺) MW:1361;

(9) a 4:2 type iron complex salt compound wherein four monoazo compoundsare coordinated to two Fe(III), i.e., [(AP-OB)₄.(Fe³⁺-Fe³⁺)](Na⁺)₂MW:1793; and

a polymeric iron complex salt compound of unknown structure (MW:2247).

In this iron complex salt compound (mixture), no unreacted monoazocompound (MW: 409+2H) was observed.

The TIC (total ion chromatography) spectrum of this iron complex saltcompound as obtained by the FD method is shown in FIG. 2 (the abscissaindicates the number of scans, and the ordinate indicates relativeintensity [ion strength]).

Example 2

Synthesis of Monoazo Compound

After 45.7 parts of 4-chloro-2-aminophenol, 110.5 parts of 35%hydrochloric acid and 244.9 parts of 2-propanol were stirred and mixed,this mixture was cooled externally to 0 to 5° C. To this mixture, 65.8parts of 36% sodium nitrite was added, and this was followed by stirringwithin the temperature range from 0 to 5° C. for 2 hours to diazotizethe 4-chloro-2-aminophenol.

Next, the NaCl which precipitated in this diazotized compound solutionwas filtered off; the filtrate obtained was added drop by drop to amixed liquor (kept at 45 to 50° C.) of 244.9 parts of 2-propanol, 64parts of a 48.7% aqueous solution of sodium hydroxide and 81.6 parts of6-tertiary octyl-2-naphthol; this mixed liquor was stirred for 2 hoursto carry out a coupling reaction; the monoazo compound precipitated wasthen collected by filtration and washed with water to yield 228 parts ofa wet cake of a monoazo compound.

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 2.

Synthesis of Iron Complex Salt Dye

After 190.5 parts (100 parts, based on solid content) of the monoazocompound wet cake obtained was gradually added to a mixed liquor of 187parts of 2-propanol and 40 parts of a 48.7% aqueous solution of sodiumhydroxide, followed by 2 hours of refluxing under heating at 83° C., 50parts of 38% ferric chloride was added, followed by 2 hours of refluxingunder heating at 83° C., to achieve metallization.

Next, this reaction mixture was dispersed in 1,025 parts of water andstirred at 30° C. for 1 hour; the product precipitated was collected byfiltration and washed with water, then dried, to yield 113 parts of aniron complex salt compound as a blackish brown powder.

The FD-MS spectrum and the TIC spectrum of the iron complex saltcompound obtained was substantially the same as spectrums of FIG. 1 andFIG. 2 for the compound obtained in Example 1.

Example 3

Synthesis of Monoazo Compound

After 45.7 parts of 4-chloro-2-aminophenol, 110.5 parts of 35%hydrochloric acid and 346.4 parts of ethylene glycol were stirred andmixed, this mixture was cooled externally to 0 to 5° C. To this mixture,67.7 parts of 36% sodium nitrite was added, and this was followed bystirring within the temperature range from 0 to 5° C. for 2 hours todiazotize the 4-chloro-2-aminophenol.

Next, this diazotized compound solution was added drop by drop to amixed liquor (kept at 45 to 50° C.) consisting of a mixed liquor of692.8 parts of ethylene glycol and 311 parts of water, 64 parts of a48.7% aqueous solution of sodium hydroxide, and 81.6 parts of 6-tertiaryoctyl-2-naphthol; this mixed liquor was stirred for 2 hours to carry outa coupling reaction; the monoazo compound precipitated was thencollected by filtration, washed with water, and dried, to yield 115.6parts of the desired monoazo compound.

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 2.

Example 4

One-pot Method

After 45.7 parts of 4-chloro-2-aminophenol, 110.5 parts of 35%hydrochloric acid and 244.9 parts of 2-propanol were stirred and mixed,this mixture was cooled externally to 0 to 5° C. To this mixture, 67.7parts of 36% sodium nitrite was added, and this was followed by stirringwithin the temperature range from 0 to 5° C. for 2 hours to diazotizethe 4-chloro-2-aminophenol.

Next, the NaCl which precipitated in this diazotized compound solutionwas filtered off; the filtrate obtained was added drop by drop to amixed liquor (kept at 45 to 50° C.) of 244.9 parts of 2-propanol, 64parts of a 48.7% aqueous solution of sodium hydroxide and 81.6 parts of6-tertiary octyl-2-naphthol; this mixed liquor was stirred for 2 hoursto carry out a coupling reaction.

After a 48.7% aqueous solution of sodium hydroxide was gradually addedto a suspension of this monoazo compound, followed by 2 hours ofrefluxing under heating at 82° C., 52 parts of 38% ferric chloride wasadded, followed by 2 hours of refluxing under heating at 82° C., toachieve metallization.

Next, this reaction mixture was dispersed in 1,180 parts of water andstirred at 30° C. for 1 hour; the product precipitated was collected byfiltration and washed with water, then dried, to yield 113 parts of aniron complex salt compound as a blackish brown powder.

Comparative Example 1

Synthesis of Monoazo Compound

In the same manner as in Example 1, except that 2-propanol was replacedwith water, a monoazo compound was obtained by a diazotizing couplingreaction.

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 2.

TABLE 2 HPLC analysis (%) Reaction time (hr) 0.5 2.0 20.0 After dryingYield (%) Example1 94.0 99.6 99.6 99.9 about 90.0 Example2 93.3 98.799.0 99.1 about 92.0 Example3 94.5 97.0 98.9 99.0 about 90.0 Comparative64.7 77.7 78.8 82.7 about 85.0 Example 1

The results of the Ames test [solvent: DMSO (dimethylsulfoxide)] for amonoazo compound (SAMPLE 1) and iron complex salt compound (SAMPLE 2)obtained in Examples 1 to 4 are shown in Tables 3 and 4, respectively.In the tables, S9mix(+) indicates the presence of metabolic activity,and S9mix(−) indicates the absence of metabolic activity. In addition, +in the columns for the strains TA-100 and TA-98 indicates that aprecipitate was observed.

TABLE 3 SAMPLE 1 μg/plate TA-100 TA-98 S9mix(−) 20 0.94 1.00 78 0.94+1.00+ 313 0.83+ 0.92+ 1250 0.85+ 1.15+ 5000 0.80+ 1.23+ S9mix(+) 20 1.221.41 78 1.26+ 1.59+ 313 1.10+ 0.82+ 1250 1.17+ 1.06+ 5000 1.46+ 0.94+

TABLE 4 SAMPLE 2 μg/plate TA-100 TA-98 S9mix(−) 20 0.85 1.00 78 0.93+1.55+ 313 0.91+ 1.27+ 1250 0.97+ 1.27+ 5000 0.90+ 1.18+ S9mix(+) 20 1.380.93 78 1.34+ 0.93+ 313 1.29+ 0.78+ 1250 1.09+ 0.78+ 5000 1.18+ 0.44+

As is evident from Tables 3: and 4, the monoazo compound and ironcomplex salt compound of the present invention yield negative results inthe Ames test and are very safe.

Example 5

Synthesis of Monoazo Compound

After 45.7 parts of 4-chloro-2-aminophenol (purity 98%), 110.5 parts of35% hydrochloric acid and 245.2 parts of 2-propanol were stirred andmixed, this mixture was cooled externally to 0 to 5° C. To this mixture,65.8 parts of 36% sodium nitrite was added, and this was followed bystirring within the temperature range from 0 to 50° C. for 2 hours todiazotize the 4-chloro-2-aminophenol.

Next, the NaCl which precipitated in this diazotized compound solutionwas filtered off; the filtrate obtained was added drop by drop to amixed liquor (kept at 45 to 50° C.) of 245.2 parts of 2-propanol, 64.1parts of a 48.7% aqueous solution of sodium hydroxide and 81.6 parts of6-tertiary octyl-2-naphthol (purity 98%); this mixed liquor was stirredfor 2 hours to carry out a coupling reaction; the monoazo compoundprecipitated was then collected by filtration, washed with water, anddried, to yield 115.4 parts (yield 90%) of a monoazo compound of thefollowing structure. The filtrate (before water washing) obtained bycollecting by filtration the monoazo compound was recovered as thefiltrate A1 (518.4 parts):

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 5.

Synthesis of Iron Complex Salt Compound

After 100 parts of the monoazo compound obtained above was graduallyadded to a mixed liquor of 189.4 parts of 2-propanol and 40.1 parts of a48.6% aqueous solution of sodium hydroxide, followed by 2 hours ofrefluxing under heating at 81° C., 50 parts of 38% ferric chloride wasadded, followed by 2 hours of refluxing under heating at 81° C., toachieve metallization.

Next, after this reaction mixture was allowed to cool to 30° C., theproduct precipitated was collected by filtration and washed with water,then dried, to yield 110 parts of an iron complex salt compound as ablackish brown powder. The filtrate (before water washing) obtained bycollecting by filtration the precipitated product was recovered as thefiltrate A2 (253.4 parts).

The FD-MS spectrum and the TIC spectrum of the iron complex saltcompound obtained was substantially the same as spectrums of FIG. 1 andFIG. 2 for the compound obtained in Example 1.

From the filtrate A1 and the filtrate A2 above, 486.2 parts of anazeotrope of 2-propanol and water (recovered IPA-1) [azeotropictemperature 80 to 82° C./2-propanol concentration 87.64% by weight] wasobtained by distillation (recovery: about 63%).

By carrying out the synthesis and recovery step as above three times,1460 parts of the recovered IPA-1 was obtained.

Example 6

One-pot Method

After 43.6 parts of 4-chloro-2-aminophenol (purity 99%), 105.1 parts of35.5% hydrochloric acid and 236.3 parts of 2-propanol were stirred andmixed, this mixture was cooled externally to 0 to 5° C. To this mixture,59.9 parts of 36% sodium nitrite was added, and this was followed bystirring within the temperature range from 0 to 5° C. for 2 hours todiazotize the 4-chloro-2-aminophenol.

Next, the NaCl which precipitated in this diazotized compound solutionwas filtered off; the filtrate obtained was added drop by drop to amixed liquor (kept at 45 to 50° C.) of 228.3 parts of 2-propanol, 61.5parts of a 48.9% aqueous solution of sodium hydroxide and 76 parts of6-tertiary octyl-2-naphthol (purity 98.3%); this mixed liquor wasstirred for 2 hours to carry out a coupling reaction.

The results of a high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound performedusing samples collected after completion of the coupling reaction areshown in Table 5.

Synthesis of Iron Complex Salt Compound

After 49.2 parts of a 48.9% aqueous solution of sodium hydroxide wasgradually added to a suspension of this monoazo compound, followed by 2hours of refluxing under heating at 82° C., 50 parts of 38% ferricchloride was added, followed by 2 hours of relfluxing under heating at82° C., to achieve metallization.

Next, after this reaction mixture was allowed to cool to 30° C., theproduct precipitated was collected by filtration and washed with water,then dried, to yield 113.3 parts of an iron complex salt compound as ablackish brown powder.

The filtrate (before water washing) obtained by collecting by filtrationthe precipitated product was recovered as the filtrate B1 (614.2 parts).From the filtrate B1, 337.8 parts of an azeotrope of 2-propanol andwater (recovered IPA-2) [azeotropic temperature 80 to 82° C./2-propanolconcentration 87.64% by weight] was obtained by distillation (recovery:about 55%).

By carrying out the synthesis and recovery step as above twice, 670parts of the recovered IPA-2 were obtained.

Example 7

Synthesis of Monoazo Compound

After 45.7 parts of 4-chloro-2-aminophenol (purity 98%), 110.5 parts of35% hydrochloric acid and 245.2 parts of the recovered IPA-1 werestirred and mixed, this mixture was cooled externally to 0 to 5° C. Tothis mixture, 65.8 parts of 36% sodium nitrite was added, and this wasfollowed by stirring within the temperature range from, 0 to 5° C. for 2hours to diazotize the 4-chloro-2-aminophenol.

Next, the NaCl which precipitated in this diazotized compound solutionwas filtered off; the filtrate obtained was added drop by drop to amixed liquor (after stirred under heating at 80° C. for an hour, cooledand kept at 46° C.) of 279 parts of the recovered IPA-1, 81.6 parts of a48.7% aqueous solution of sodium hydroxide and 81.6 parts of 6-tertiaryoctyl-2-naphthol (purity 98%); this mixed liquor was stirred for 2 hoursto carry out a coupling reaction; the monoazo compound precipitated wasthen collected by filtration, washed with water, and dried, to yield113.7 parts (yield 88.7%) of a monoazo compound. The filtrate (beforewater washing) obtained by collecting by filtration the monoazo compoundwas recovered as the filtrate A3 (568 parts):

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 5. The chart of the HPLC analysis is shown in FIG. 3.

Synthesis of Iron Complex Salt Compound

After 100 parts of the monoazo compound obtained above was graduallyadded to a mixed liquor of 189 parts of the recovered IPA-1 and 40.1parts of a 48.6% aqueous solution of sodium hydroxide, followed by 2hours of refluxing under heating at 82° C., 50 parts of 38% ferricchloride was added, followed by 2 hours of refluxing under heating at82° C., to achieve metallization.

Next, after this reaction mixture was allowed to cool to 30° C., theproduct precipitated was collected by filtration and washed with water,then dried, to yield 110 parts of an iron complex salt compound as ablackish brown powder. The filtrate (before water washing) obtained bycollecting by filtration the precipitated product was recovered as thefiltrate A4 (245 parts).

The FD-MS spectrum and the TIC spectrum of the iron complex saltcompound obtained was substantially the same as spectrums of FIG. 1 andFIG. 2 for the compound obtained in Example 5.

From the filtrate A3 and the filtrate A4 above, 318 parts of anazeotrope of 2-propanol and water (recovered IPA-3) [azeotropictemperature 80 to 81° C.] was obtained by distillation (recovery: about62%).

Example 8

Synthesis of Monoazo Compound

In the quite same manner as in Example 7, 115.6 parts of the monoazocompound was obtained using the recovered IPA-1 obtained in Example 5.And the filtrate A5 (563 parts) was recovered same manner as in Example7.

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 5.

Synthesis of Iron Complex Salt Compound

In the quite same manner as in Example 7, 112 parts of the desired ironcomplex salt compound was obtained using the recovered IPA-1 obtained inExample 5. And the filtrate A6 (243 parts) was recovered same manner asin Example 7.

The FD-MS spectrum and the TIC spectrum of the iron complex saltcompound obtained was substantially the same as spectrums of FIG. 1 andFIG. 2 for the compound obtained in Example 5.

From the filtrate A5 and the filtrate A6 above, 489.8 parts of anazeotrope of 2-propanol and water (recovered IPA-4) was obtained bydistillation (recovery: about 61%).

Example 9

One-pot Method

After 43.6 parts of 4-chloro-2-aminophenol (purity 99%), 105.1 parts of35% hydrochloric acid and 236 parts of the recovered IPA-2 were stirredand mixed, this mixture was cooled externally to 0 to 5° C. To thismixture, 59.9 parts of 36% sodium nitrite was added, and this wasfollowed by stirring within the temperature range from 0 to 5° C. for 2hours to diazotize the 4-chloro-2-aminophenol.

Next, the NaCl which precipitated in this diazotized compound solutionwas filtered off; the filtrate obtained was added drop by drop to amixed liquor (after stirred under heating at 80° C. for an hour, cooledand kept at 46° C.) of 254 parts of the recovered IPA-2, 65.1 parts of a48.9% aqueous solution of sodium hydroxide and 76 parts of 6-tertiaryoctyl-2-naphthol (purity 98.3%); this mixed liquor was stirred for 2hours to carry out a coupling reaction.

The results of a high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound performedusing samples collected after completion of the coupling reaction areshown in Table 5.

After 49.2 parts of a 48.9% aqueous solution of sodium hydroxide wasgradually added to a suspension of this monoazo compound, followed by 2hours of refluxing under heating at 82° C., 50 parts of 38% ferricchloride was added, followed by 2 hours of refluxing under heating at82° C., to achieve metallization.

Next, after this reaction mixture was allowed to cool to about 30° C.,the product precipitated was collected by filtration and washed withwater, then dried, to yield 113 parts of an iron complex salt compoundas a blackish brown powder.

The filtrate (before water washing) obtained by collecting by filtrationthe precipitated product was recovered as the filtrate B2 (660 parts).

The FD-MS spectrum and the TIC spectrum of the iron complex saltcompound obtained was substantially the same as spectrums of FIG. 1 andFIG. 2 for the compound obtained in Example 5.

From the filtrate B2 above, 369.9 parts of an azeotrope of 2-propanoland water (recovered IPA-5) was obtained by distillation (recovery:about 56%).

Example 10

Synthesis of Zirconium Complex Salt Compounds

A zirconium complex salt compound was obtained in the same manner oftreatment as in Example 5, except that the aqueous solution of ferricchloride used in the metallizing reaction of Example 5 was replacedwith, zirconium chloride (IV).

In the same manner as in Example 7, except that the azeotrope of2-propanol and water obtained from the filtrate in the synthesistreatment for this zirconium complex compound was used, and that theaqueous solution of ferric chloride used in Example 7 was replaced withzirconium chloride (IV), another zirconium complex salt compound wasobtained.

Example 11

Synthesis of Aluminum Complex Salt Compounds

An aluminum complex salt compound was obtained in the same manner oftreatment as in Example 6, except that the aqueous solution of ferricchloride used in the metallizing reaction of Example 5 was replaced withaluminum chloride (III).

In the same manner as in Example 9, except that the azeotrope of2-propanol and water obtained from the filtrate in the synthesistreatment for this aluminum complex compound was used, and that theaqueous solution of ferric chloride used in Example 9 was replaced withaluminum chloride (III), another aluminum complex salt compound wasobtained.

The monoazo compound and the metal complex salt compound obtained inExamples 5 to 11 yield negative results in the Ames test and are verysafe.

Comparative Example 2

Synthesis of Monoazo Compound

In the same manner as in Example 7, except that the recovered IPA-1 wasreplaced with water, a monoazo compound was obtained by a diazotizingcoupling reaction.

The results of high performance liquid chromatography analysis (HPLCanalysis) for the production rate (%) of this monoazo compound are shownin Table 5. The chart of the HPLC analysis is shown in FIG. 4.

Synthesis of Iron Complex Salt Compound

An iron complex salt compound was obtained by the same metallizingreaction as in Example 7, except that the recovered IPA-1 used inExample 7 was replaced with water. This iron complex salt compound wasfound to contain the unreacted monoazo compound.

TABLE 5 HPLC analysis (%) Reaction time (min) 30 120 After drying Yeild(%) Example5 93.20 97.39 98.64 about 90.0 Example6 94.22 98.34 98.52 —Example7 93.38 98.61 98.82 about 88.7 Example8 95.21 98.00 98.56 about90.2 Example9 93.50 97.05 97.55 — Comparative 75.94 85.07 85.37 about75.5 Example 2

Next, example embodiments of toners of the present invention fordeveloping electrostatic images containing the charge control agent asobtained by the manufacturing process of the present invention aredescribed in Examples I through VII below.

Example I

Styrene-acrylic copolymer resin (produced by Sanyo Kasei Co., Ltd.,trade name: HIMER SMB600) . . . 100 parts

Low polymer polypropylene (produced by Sanyo Kasei Co., Ltd., tradename: Biscal 550P) . . . 5 parts

Carbon Black (produced by Mitsubishi Chemical Corporation, trade name:MA-100) . . . 7 parts

Charge control agent (iron complex salt compound obtained in Example 1).. . 1 part

The above ingredients were uniformly pre-mixed using a high-speed millto yield a premix, which was then kneaded in a molten state using a heatroll, cooled and thereafter roughly milled using an ultracentrifugalmill. The rough milling product obtained was finely pulverized using anair jet mill equipped with a mechanical classifier to yield a blacktoner 5 to 15 μm in particle diameter.

Five parts of this toner was admixed with 95 parts of an iron powdercarrier (produced by Powdertech, trade name: TEFV200/300) to yield adeveloper.

After the developer obtained was thoroughly stirred, the amount ofcharges was determined by the blowoff method (Toshiba Chemical blowoffcharge analyzer [trade name: TB-200] used). The results of determinationare shown in FIG. 5. In FIG. 5, the abscissa indicates developer mixingtime (min), and the ordinate indicates the amount of charges (−μC/g).

The amount of blowoff charges of this developer was stable underlow-temperature low-humidity conditions and under high-temperaturehigh-humidity conditions, demonstrating. good storage stability. Whenthis toner was used to repeatedly form toner images using a commercialcopying machine, the charge stability and retention were good, andhigh-quality images with no offset phenomenon, image density reductionor fogging were obtained.

Example II

Polyester resin (produced by Nippon Synthetic Chemical Industry Co.,Ltd., trade name: HP-301) . . . 100 parts

Low polymer polypropylene (produced by Sanyo Kasei Co., Ltd., tradename: Biscal 550P) . . . 5 parts

Carbon Black (produced by Mitsubishi Chemical Corporation, trade name:MA100) . . . 7 parts

Charge control agent (iron complex salt compound obtained in Example 2). . . 1 part

The above ingredients were treated in the same manner as in Example I toyield a black toner and a developer, and the developer was evaluated.The amount of blowoff charges of this developer was stable underlow-temperature low-humidity conditions and under high-temperaturehigh-humidity conditions, demonstrating good storage stability. Whenthis toner was used to repeatedly form toner images, the chargestability and retention were good, and high-quality images with nooffset phenomenon, image density reduction or fogging were obtained, asin Example I.

Example III

Styrene-2-ethylhexyl methacrylate copolymer resin . . . 100 parts

Triiron tetraoxide [produced by Toda Kogyo Corporation, trade name:EPT-500] . . . 70 parts

Low polymer polypropylene [produced by Sanyo Kasei Co., Ltd., tradename: Biscal 550P] . . . 3 parts

Carbon Black [produced by Mitsubishi Chemical Corporation, trade name:MA-100] . . . 7 parts

Charge control agent (iron complex,salt compound obtained in Example 1). . . 2 parts

The above ingredients were uniformly pre-mixed using a ball mill toyield a premix, which was then kneaded in a molten state using a heatroll, cooled and thereafter roughly milled, finely pulverized andclassified by size to yield a one-component toner 5 to 15 μm in particlediameter.

When this toner was used for a commercial copying machine to form tonerimages, fogging-free images with good thin-line reproducibility wereobtained. Also, even in continuous copying, the image density wasstable, with no staining due to toner splashing.

Comparative Example I

A toner and a developer were prepared in the same manner as in ExampleI, except that the charge control agent of the present invention used inExample I (iron complex salt compound obtained in Example 1) wasreplaced with a crystalline iron complex salt compound of the followingstructure, and their charge characteristics were compared. The resultsare shown in FIG. 5.

Example IV

Styrene-acrylic copolymer resin (produced by Sanyo Kasei Co., Ltd.,trade name: HIMER SMB600) . . . 100 parts:

Low polymer polypropylene (produced by Sanyo Kasei Co., Ltd., tradename: Biscal 550P) . . . 3 parts

Carbon Black (produced by Mitsubishi Chemical Corporation, trade name:MA-100) . . . 7 parts

Charge control agent (iron complex, salt compound obtained in Example 7). . . 1 part

The above ingredients were uniformly pre-mixed using a high-speed millto yield a premix, which was then kneaded in a molten state using a heatroll, cooled and thereafter roughly milled using an ultracentrifugalmill. The rough milling product obtained was finely pulverized using anair jet mill equipped with a mechanical classifier to yield a blacktoner 5 to 15 μm in particle diameter.

Five parts of this toner was admixed with 95 parts of an iron powdercarrier (produced by Powdertech, trade name: TEFV200/300) to yield adeveloper.

After the developer obtained was thoroughly stirred, the amount ofcharges was determined by the blowoff method (Toshiba Chemical blowoffcharge analyzer [trade name: TB-200] used).

The amount of blowoff charges of this developer was still more stableunder low-temperature low-humidity conditions and under high-temperaturehigh-humidity conditions, demonstrating still better storage stability.When this toner was used to repeatedly form toner images using acommercial copying machine, the charge stability and retention werestill better, and high-quality images with no offset phenomenon, imagedensity reduction or fogging were obtained.

Example V

A toner and a developer were prepared in the same manner as in ExampleIV, except that the charge control agent used in Example IV (ironcomplex salt compound obtained in Example 7) was replaced with the ironcomplex salt compound obtained in Example 8, and developing wasconducted therewith; high-quality images with no image density reductionor fogging were obtained as in Example IV.

Example VI

Polyester resin (produced by Nippon Synthetic Chemical Industry Co.,Ltd., trade name: HP-301) . . . 100 parts

Low polymer polypropylene (produced by Sanyo Kasei Co., Ltd., tradename: Biscal 550P) . . . 3 parts

Carbon Black (produced by Mitsubishi Chemical Corporation, trade name:MA100) . . . 7 parts

Charge control agent (iron complex salt compound obtained in Example 9). . . 1 part

The above ingredients were treated in the same manner as in Example IVto yield a black toner and a developer, and the developer was evaluated.The amount of blowoff charges of this developer was stable underlow-temperature low-humidity conditions and under high-temperaturehigh-humidity conditions, demonstrating good storage stability, as inExample IV. When this toner was used to repeatedly form toner images thecharge stability and retention were good, and high-quality images withno offset phenomenon, image density reduction or fogging were obtained,as in Example IV.

Example VII

Styrene-2-ethylhexyl methacrylate copolymer resin . . . 100 parts

Triiron tetraoxide [produced by Toda Kogyo Corporation, trade name:EPT-500] . . . 70 parts

Low polymer polypropylene [produced by Sanyo Kasei Co., Ltd., tradename: Biscal 550P] . . . 2 parts

Carbon Black [produced by Mitsubishi Chemical Corporation, trade name:MA-100] . . . 7 parts

Charge control agent (zirconium complex salt compound obtained inExample 10) . . . 2 parts

The above ingredients were uniformly pre-mixed using a ball mill toyield a premix, which was then kneaded in a molten state using a heatroll, cooled and thereafter roughly milled, finely pulverized andclassified by size to yield a one-component toner 5 to 15 μm in particlediameter.

When this toner was used for a commercial copying machine to form tonerimages, fogging-free images with good thin-line reproducibility wereobtained. Also, even in continuous copying, the image density wasstable, with no staining due to toner splashing.

What is claimed is:
 1. A process for preparing a metal complex saltcompound of formula (I):

wherein R is a normal or branched alkyl group having 4-12 carbon atoms Yis a halogen atom or a normal or branched alkyl group having 1-5 carbonatoms; each of p and q shows the number of corresponding monoazocompounds coordinated to the metal M; such that p is 1, 2, 3 or 4; q is0, 1, 2 or 3; and the sum of p+q is an integer of 1-6; each of L₁ and L₂is —O—; one of L₃ and L₄ is —O—, while the other is an —OH group or an—O³¹ ion; M is iron, nickel, aluminum, titanium or zirconium;(M^(x+))_(m) represents an m number of metals of atomic valence x; suchthat m is an integer of 1-4; and x is an integer of 2 or more; Z− is thenegative charge in the parentheses; and (A³⁰ )_(n) is a hydrogen ion oran alkali metal ion; and n=Z; which comprises an initial step ofdiazotizing coupling reaction to produce a monoazo compound of formula(II):

 wherein R and Y are the same as defined above; in which a corresponding4-Y-2-aminophenol wherein Y is the same as defined above is diazotizedto the corresponding diazonium salt and the diazonium salt is in turncoupled with a corresponding 6-R-2-naphthol wherein R is the same asdefined above to form the monoazo compound of formula (II); in which amonohydric alcohol is used as solvent in the diazotizing couplingreaction; and which comprises a subsequent step of metallizing theresulting monoazo compound of formula (II) with iron, nickel, aluminum,titanium or zirconium to produce a metal complex salt compound in ametallizing reaction in which a monohydric alcohol is used as solvent,whereby to obtain a metal complex salt compound of not less than about90% purity.
 2. The process of claim 1 wherein the monohydric alcohol is2-propanol.
 3. The process of claim 1 wherein Y is a halogen atom. 4.The process of claim 1 wherein R is a tert-octyl group and Y ischlorine.
 5. The process of claim 1 wherein iron chloride is used as ametallizing agent in the metallizing reaction.
 6. The process of claim 1wherein, after the metallizing reaction is carried out, the processcomprises a further step of cooling the reaction mixture and separatingthe resulting precipitated metal complex salt compound from the cooledreaction mixture.
 7. A process for preparing a metal complex saltcompound of formula (I)

wherein R is a normal or branched alkyl group having 4-12 carbon atoms;Y is a halogen atom or a normal or branched alkyl group having 1-5carbon atoms; each of p and q shows the number of corresponding monoazocompounds coordinated to the metal M; such that p is 1, 2, 3 or 4; q is0, 1, 2 or 3; and the sum of p+q is an integer of 1-6; each of L₁ and L₂is —O—; one of L₃ and L₄ is —O—, while the other is an —OH group or an—O³¹ ion; M is iron, nickel, aluminum, titanium or zirconium;(M^(x+))_(m) represents an m number of metals of atomic valence x; suchthat m is an integer of 1-4; and x is an integer of 2 or more; Z− is thenegative charge in the parentheses; and (A³⁰ )_(n) is a hydrogen ion oran alkali metal ion; and n=Z; which comprises metallizing a monoazocompound of formula (II):

 wherein R and Y are the same as defined above and wherein the monoazocompound of formula (II) is prepared by a diazotizing coupling reactionin which a corresponding 4-Y-2-aminophenol wherein Y is the same asdefined above is diazotized to the corresponding diazonium salt, and thediazonium salt is in turn coupled With a corresponding 6-R-2-naphtholwherein R is the same as defined above to form the monoazo compound offormula (II), the diazotizing coupling reaction being carried out in amonohydric alcohol as solvent; with a metallizing agent containing ametal M as defined above in a monohydric alcohol as solvent,sufficiently to react substantially completely the monoazo compound offormula (II) and to produce a reaction mixture containing substantiallyno unreacted monoazo compound and containing the metal complex saltcompound of formula (I) in high yield and in a high purity of not lessthan about 90%.
 8. The process of claim 7 wherein 4-chloro-2-aminophenolis diazotized in 2-propanol as monohydric alcohol solvent, and theresulting diazotized compound is subjected as diazo component to acoupling reaction with 6-tertiary octyl-2-naphthol as coupling componentin 2-propanol as monohydric alcohol solvent to form the monoazo compoundof formula (II).